Dong-Keun Ki, Alberto F. Morpurgo
Suspended graphene nano-ribbons that form spontaneously during current annealing of suspended graphene flakes have been investigated experimentally. Transport measurements show the opening of a transport gap around charge neutrality due to the formation of a random array of "Coulomb islands", coexisting with quantum Hall conductance plateaus appearing at already moderate values of magnetic field $B$. Upon increasing $B$, the transport gap is rapidly suppressed, and is taken over by a much larger energy gap due to interaction-induced electronic correlations. Our observations show that suspended nano-ribbons allow the investigation of phenomena that could not so far be accessed in ribbons on SiO$_2$ substrates.
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http://arxiv.org/abs/1203.0540
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